Numerical Simulation of Blade Vortex Interaction (BVI) In Helicopter Using Large Eddy Simulation (LES) Method

In this paper, computational fluid dynamics (CFD) viscous flow simulation of BO-105 isolated helicopter rotor blades was simulated using commercially available STAR-CCM + software. The aim of these simulations is to capture the complex flow dynamics and blade vortex interaction (BVI) noise generation in hover configuration. In order to capture the complex nature of BVI and viscous wake precisely and accurately, large eddy simulation (LES) method was used. Overset mesh was used as mesh technique. The mesh technique and number of cells play an important role in capturing this complex phenomenon. Computational aero-acoustics (CAA) method was used to capture the noise generated due to the rotation of rotor blades. Ffowcs-Williams–Hawkings unsteady equation formulation was used to capture the far-field acoustics. Both CFD and CAA together helped to obtain the flow dynamics as well as far-field noise generated. The hover performance parameters obtained from numerical simulation showed good agreement with the theoretical and experimental data. The frequency spectral analysis of the acoustical data showed number of peaks that correspond to blade passage frequency (BPF) and its harmonics. The sound pressure level SPL of receivers at in Cartesian coordinates at 45° elevation in 1st and 4th quadrants was greater compared to that of rotor plane receivers. The maximum SPL of 121 dB was measured by receiver directly below the rotor hub of the helicopter.